thanks for the reply, i was thinking on something along the lines of limiting the post production part, even though some might be necessary..
- maybe 5-10 people running away from something ridiculous like a fluffy bunny.. something comical

- maybe the other way around; something really serious, but i'm having trouble because anything well-thought and nicely done would take excessive post-processing and i really want to avoid that.. so i'm not looking for exact ideas; maybe pointing in one direction, discussing it etc..

You can also think about after the apocalypse and what happens then... people with gas masks, scavenging for any type of vegetation.

Or maybe a more biblical reference or something with the 4 horsemen? Put some time in researching them and see how you can best represent them in photography.

Think of different ways the world can end... you have the standard bomb, maybe some sort of super virus, although I tend to think of apocalypse as having alot of fire and burning. But honestly, I think the zombie theme might work....

Yeah the bunny thing could very well work. I imagine that most of the shots will be to the serious side and, having something with comical relief may work. Maybe add an inferno behind the bunny for effect in post.

He doesn't want to have to do post processing.
Just out of curiosity, why are you so adamant about not doing post?
Do you have limited skill and knowledge in post processing?

Take the opportunity in this challenge to strengthen your weaknesses.
Due to the nature of the contest most all submissions will have heavy post work done to them because the apocalypse isn't something you can just go out and take photos of.
You'll have to take photos with post pro in mind then manipulate the photo.
Unless you do something subtle, like a church sign that reads: "the end is near" or something like that.
But that's pretty simple compared to what others will be doing.

actually i'm kind of a geek in photoshop, been doing stuff for years.. but i don't want my photo to be all fake.. here's my thoughts of what i'm almost certain i'll do..

a friend of mine has this freakishly looking mask and i'm going to take pictures (5-10) of him chasing after a guy/girl and because i'd make every shot separately on a tripod i'd make a composite and light every subject separately.
if i'd do this at night time the light fall and the effect of the flash would compromise the whole scene so i need to do this when it's still bright.. i'm thinking of location now.. maybe an abandoned warehouse? i need a static location with no movement because of the merging i'm going to do.

i'm all packed and ready to shoot that zombie-monster-invasion thing but i've just read an additional article on the competition. it talks about the ice caps melting, volcanoes, climate changes, the recession and wars.. so i'd had to make an apocalypse themed photo with something of that.. only wars, recession and climate changes seem at least possible to do really..